Indesit IDE 750 dish washer. Settings issue?

I have a 4-5 year old Indesit IDE 750 dish washer- i know i should be greatful it has lasted that long :)
However, it has now stopped & the timer/ fuction control does not work properly (varies the duration of each setting, but not the correct time, or just makes the beeping noise & stops?)
I have started it off again at "rapid" which should be 24 mins, but after a while it changes to 1 hr 48 mins! I let it run but now an error message A05 has appeared???
HELP